The invention relates to a filter sheet material in motor vehicles, especially a filter material for the removal of unpleasant odours in the passenger cabin of motor vehicles. Due to the continuously rising traffic volume passengers of motor vehicles are exposed to a high degree of unpleasant odours of exhaust fumes. German Offenlegungsschrift 37 40 091 discloses a pourable filter sheet material comprising a catalyst. German patent 25 03 615 discloses a multi-layered filter sheet material consisting of a support layer, at least one intermediate layer of polymer micro-fibres and a porous cover layer.
German patent 33 04 349 as well as U.S. Pat. No. 4,510,193 disclose a filter sheet material consisting of an air-permeable, pliable, especially textile support which is covered only partially with a uniformly distributed adhesive on which adsorber particles, especially active carbon beads are fixed. Said prior art furthermore concerns the use of such filter materials containing active carbon as adsorbant for protective suits.
The German Offenlegungsschrift 32 28 156 as well as the European Patent 100 907 having the same priority disclose that the removal of unpleasant odours is achieved by active carbon as an adsorbant of choice. However, said adsorber particles may be only partially covered by an adhesive, because otherwise, the pores are not sufficiently accessible and therefore the desired effect will not be achieved. Furthermore, it is advisable that the adsorber particles will be protected against a blocking of the pores by dust and soot particles, whereby the use of a pre-filter sheet material is necessary.
The German Offenlegungsschrift 39 04 623 discloses an odour filter sheet material, wherein a particle filter sheet material and an adsorption filter sheet material are provided directly side by side which two components of the filtering means are both folded zigzag. In this prior art device, the air first passes the particle filter sheet material and then the adsorption sheet material. This prior art device has the disadvantage that the individual layers of the filter sheet material must be manufactured separately and that the further processing to obtain the filter sheet material is not easily achieved, due to the multi-layer structure.